The present invention relates generally to antennas and, more particularly, to antennas for hand-held cellular or wireless telephones. Cellular telephone antennas are typically vertically polarized omnidirectional antennas. Since no vertically polarized axis has any gain advantage in any particular direction, the antenna radiates equally well in all directions. A graphical representation of field strength resulting from a vertically polarized omnidirectional antenna is a well known “donut” pattern. Since the directional location of the nearest receiving station is not usually known to a user of a cellular telephone, omnidirectionality has long been considered to be a requirement for cellular telephone antenna design. Clearly, however, an omnidirectional antenna is not energy efficient because a large proportion of the radiated energy is not directed toward a desired receiver antenna. Another disadvantage of omnidirectional antennas on hand-held transmitters is that the user, and in particular the user's head, is exposed to significant levels of radiated radio-frequency (RF) energy.
From an energy efficiency and user safety standpoint, it would be much more desirable to provide a hand-held cellular telephone with a radiated beam pattern that is always shaped and directed to provide a desired signal strength at a receiver station, while at the same time minimizing user exposure to the radiation. The present invention is directed to this end.